Am I eligible to get admission in any IIM? I have 77% in 10th CBSE, 78% in 12th CBSE and 82% in graduation.

Yes is the answer for eligibility based on your past academic scores as most of the B Schools asked for 1st class in 10th,12th and Graduation. But after that, its generally depends on your CAT score plus GD/What and PI performance. This in addition to the weight-age provided to your past academic sc